Air conditioning



Nov.' 2l, 1939. w s HAMlLTON 2,181,053

AIR CONDITIONING 'Filed Aug. 9, 1958 2 sheets-sheet 1 .n .IIVUHH INVE'NTOR. M-

Nov. 2.1.1939. w. s. H. .HAMILTON l 4 V2,131,053

` AIR oNDITIoNING Filed Aug. 9, 19:58 2 sheets-sheet 2 AIR COND/Tla/NG CONTROL SDV/TCU s All/- v r/PA Ms.

L UB 0/1. PRESS HSW.

INVENTOR.

PILOT lef/frs Jerk/c Entr l @AM ATTORNY Patented Nov. 21, 1939 PATENT ori-'ica AIB CONDITIONING William S. H.

Hamilton, Larchmont, N. Y., as-

signor to The New York Central Railroad Company, a corporation of New York Application August 9, 1938, Serial No. 223,958

18 Claims.

This invention relates to anl air conditioning and illuminating system for railway passenger cars, and the general object of the invention is to provide a4 simple, reliable and comparativelyfinexpensive system of this character designed for either cooling or heating the circulated air and also for illuminating the car.

The present invention provides for these purposes a system using a Diesel engine to drive its working parts, this engine being large enough to handle the load on one car only. It is therefore different from other systems so far developed which use a Diesel engine generator set at the head end of a train to furnish powei` to a number of cars-throughout the train.

It is uneconomical to design an air conditioning system for modern passenger cars and disy regard the energy requirements for lighting and battery charging. 'I'he blower which is used to o circulate air within the car is of necessity a very important piece of apparatus in such a system and means must be taken to guard against its failure so far as is reasonably possible. The best way to insure continuity of operation is to connect it 5 to a storage battery with suitable meansl for recharging the same.

It is also necessary, especially on certain railroads, 'to provide means for operation of the air conditioning system withoutv running the 0 Diesel engine, onaccount of Iobjections to noise and exhaust gas odorsin congested terminals, l

etc.

Since the Diesel engine will have to operate during the winter in order to provide energy for 5 lights and battery charging when the total output required will be low on account of the air conditioning compressornot being operated, some of the availabe capacity is also utilized for an electric heater located near the evaporator in the air discharge from the blower. This has the advantage that the circulated air ably warm while 'steam is oi the car during changes atl terminals, etc., and not make it necessaryto shut down the blower at this time.

; My invention provides a system which meets these conditions while reducing to a possible minimum the required number of working parts and the expense of installation and maintenance.

Inthe accompanying drawings illustrating the invention- Fig. 1 'is a view showing the Diesel engine, synchronous motor, magnetic clutch tioning elements of the system.

Fig. 2 is a wiring diagram of the circuits and associated parts 0i the systemand air condi-l can be kept reasoning medium to the car at the same time.

The system emp .oys a Diesel engine D-*E connected through a magnetic clutch M-C to an A. C. synchronous motor M-G and an air conditioning refrigerant compressor C-P. The Diesel engine is approximately H. P., thesynchro- 5 nous motor 2.3 H. P. (or 15 kw. as a generator) and the compressor of 6-'7 tons capacity. 'I'he electric heater E-H shown is6 kw.

The Diesel engine is arranged to operate at a constant speed under control of a governor (not 10 v shown) and this speed is assumedY to be 1800 R. P. M. The A. C. synchronous motor is designed to operate at the same speed and is of the 3 phase, 220 volt type, this being the standard voltage available for stand-by service on most 1l railroads. 'I'he air conditioning compressor can be either directly connected, as shown, to, or belt driven from, the yshaft of the synchronous motor. as most convenient. e l

'I'he cooling portion of the air conditioning sys- 20 tem can b e of any conventional type with a particular exception, that shown being of compressor-expander-condenser type including the compressor C-P, condenser C, evaporator or cooling coil E, receiver Re, expansion valve E-V, and associated piping. It is preferred to use a non-i toxic volatile refrigerant, such as dichlorodiiiuoromethane, which may be directly expanded into the evaporator E, but any equivalent volatile refrigerant may be used. 'I'he particular exception noted is that of the provision of a by-pass B-P containing an electromagnetic. by-passvalve B-P-V which is normally closed to permit normal circulation of the refrigerant, but which when opened will prevent Viiow of the refrigerant through the cooling circuit and allow only flow of the refrigerant vapor through the idlingcin cuit formed by the by-pass and compressor as the latter operates. When the by-pass valve is open to permit such use of the by-pass circuit the synchronous motor may operate as a generator driven u by the Diesel engine without supplying any cool- A magnetic clutch MC is provided for automatically connecting the Diesel engine with and disconnect' ing it from the synchronous motor. Means, such as a clutch Cl, may also be provided to discon-l nect the compressor from the synchronous motor during the winter or at other times when cooling is not required. While clutch MC is disclosed as a magnetic clutch it is al'so feasible to use in its stead a type of free wheel clutch in which the clutch engages and transmits power as soon as the speed of the Diesel engine exceeds the speed QI the synchronous motor. Associated with the determined speed below evaporator E and heater E-H is a blower fan B-F for circulating the air to be cooledv or heated and supplied to the car.

The electric circuits of the system shown in Fig'. 2 include, besides the synchronous motor, magnetic clutch, blower and heater, lights for illuminating the car and various operating and control features which I will now proceed to describe.

The synchronous motor is shown as a Y-connected motor although a delta-connected one could be used. The amortisseur winding (not shown) for use in starting, also a field winding F--W excited from the battery B as shown.

A voltage regulator V-R is provided for holding constant voltage when the motor acts as a generator. This is shown as of the conventional carbon' pile type, adapted to work irom- A. C. through a rectifier as shown, and in which a spring tends to operate an arm to compress the carbons and a solenoid tends to separate them as the voltage increases. Any of the other types of A. C. voltage regulators on the market could be used instead if desired.

The voltage regulator V-R also performs a second useful function in that when the synchronous motor is running as a motor it tends to maintain the line voltage constant by varying the eld of the synchronous motor (and the power factor).

centrifugal switch C-S which closes when a prereached and this causes the field contacter F to close and excite the field.

The blower ian B-F for circulating air through the car is operated from Operation of the blower from the battery insures theI greatest reliability and also insures that the supply of air will not be interrupted no matter how-the rest of the system is being operated.

The blower is shown as compound wound with a small amount of resistance in the field circuit controlled by an interlock on contactor AC3, the purposeyof this being to make the speed of the blower approximately the same when the battery is being charged from the rectifier R as when it is running from the battery, by weakening the field somewhat when the battery is not being charged.

The rectier R for charging the storage battery can be any one of the conventional types of rectifiers now available. A motor generator set can be used instead if desired.

The layout of this system is such as to enable the size of battery B to be reduced to a minimum in order to secure minimum weight. Ordinarily a 16-cell, 300 a. h. lead battery will be found ample for the purposes required of it by this i system. This contrasts with the 32 cell, 600 a. h.

lead battery required for cars using the electromechanical system of air conditioning.

This system` contemplates operating the car lights normally from A. C. through transforrriersv indicated as TI, T2 and T3, the lamps themselves operating at 30 volts. into two classes, those operated from A. C. only (marked A.Y C. Lights) which are not lighted when A. C. supply is not available, and those operated either from A. C. supply or D. C. from the battery (marked A.4 C.-D. C. Lights). It is' assumed that the lighting circuits would be so distributed in the car that with A, C, Supply motor is provided with an synchronous speed is pass valve around the compressor the battery B which isl indicated as a lG-cell battery of the lead type.-

These would be divided.

available and all lights turned on, approximate equal loading would be obtained on the 3 phases 'of the power supply.

4Three transfer relays LRI, LR2 and LR3 are provided to transfer the A. C.-D. C. lights from D. C. to A. C. whenever this is available.

The relative 'number of 4A. C. or A. C.--D.l C.

lights would depend onithe type of car under consideration and the amount of illumination re- -quired during the time that the only source of power supply on the car was from the battery.

It is to be noted particularly that the lights are never operated from the battery while it is being charged so that a lamp regulator is not required with this system.

'I'he system is provided with push buttons marked Engine start, Engine stop, an air conditioning controlswitch (marked H, "Off and C) and four pilot lights PLI, PL2, PL3,

` PLA, located in practice on a panel board in the car in approximately the same location as the regulator and control panels ordinarily used. The connections for controlling the air conditioning are indicated, but no attempt has been made to show all the details which are involved in such systems.

Of the four pilot lights, PLI indicates whenv the external A. C. power supply is applied to the 220 Volt receptacle, the PL2 indicates when the engine is running as shown by the closure of a pressure switch P-S connected to the lubricating oil system of the engine, the PL3 indicates when the car is cooling as indicated by the bybeing closed, and the PL4 indicates when electric heat is being used.

A number of contactors and relays are provided as shown and the functioning of each of these will be described below. They are all assumed to be of the magnetically operated type with D. C.

l coils connected to the battery.

Engine start is ES and ap' plies current from the battery B to a small start ingfmotor SM connected to the Diesel enginev to turn it over so that it will commence firing. This l button is held down until the Engine run pilot light PL2 glows, which will occur as soon as the engine has speeded up suiciently to close a lubricating-oil-pressure-switch PS. As soon as this occurs the engine starting button can be released and the starting motor thereby disconnected from the battery.

Pressing the Engine start button also energizes a coil EBC marked Engine run which is assumed to represent an electrically operated mechanism in connection with the fuel injection pumps on the engine which when energized will enable the governor to move the fuel pump racks to the wide open position and secure full speed. Y

Should this circuit be broken for any reason, deenergization. of this coil will cause the racks controlling th'e fuel pumps to move to the off position in which no more fuel can be injected into the engine and the engine will stop. It will be noted that this engine starting button is bypassed by a contact on relay R2 particular circuit remainsenergized even after the engine starting -button has been released. It is however broken and R-2 cut out should the Engine stop button be pressed at any time.

Relay R2 also closes the circuit to the magso that this netic clutch so that the Diesel engine, as it comes up to speed, also brings the synchronous motor and compressor up to speed with it. AThrough another interlock on relay R-2, contactor F which controls the field of the synchronous motor is closed and this'causes the voltage to build up under the control o! the voltage regulator.

The circuit through the "Engine start" and moved to the Ci' position a circuit will be completed through the thermostat TH! contacts (closed as shown if the car is warmer than the desired temperature), the centrifugal switch C-S on the 'synchronous motor and the coil of relay R3. Picking up of relay R3 energizes the by-pass valve and closes the by-pass a'round the compressor which will then commence to compress the refrigerant and cool the car.

It will be noted thatthis arrangement keeps the compressor from loading up until the Diesel engine and synchronous motor have reached nearly full speed, thus facilitating starting of the Diesel engine.

When -the car has cooled suiliciently, the thermostat TH2 opens its contacts, deenergizing relay R3. This in turn deenergies the bypass valve, thus opening the by-pass and stopping the cooling action of the compressor.A

The contactor AC3 through which power is supplied to the rectifier for charging the battery.

closes as soon as contactor R3 opens.

When it is desired to stop the Diesel engine the,

Engine stop button is pressed. 'I'his deenergizes relay R2 and the coil marked Engine run.

This latter moves the racks of the fuel injection pumps to the oi position and stops the engine.' All other circuits which have been described above are also deenergized and the lights 'transferred back to the battery.

In the use of the apparatus for heating air the engine is started in the manner described above. When the air conditioning control switch is moved to the H position, relay RI is energized through thermostat THI. Relay RI in turn energizes the coil of contactor ACS, which connects the electric heater to the AC lines. When the car has heated up suiliciently thermostat THI opens its contacts and opens A05, disconnecting the heater from the line.

In using a wayside source of current supply, assuming that the Diesel engine is shut down, and the air conditioning control switch is in the off position, the wayside plug WP is inserted in the wayside socket or receptacle W-S whereby the auxiliary contacts shown are clos d and current from the battery energizes the coil of 'contactor AC2 through the bottom, contact of Engine start button and interlocks on contactor ACl and relay R2.

Closing of contactor AC2 supplies power to the lights and the transfer relays LRI, LR2 and LR3.

' pick up to the AC position. Closing of interlock on contactor AC2 also energizes contactor AC3 and furnishes current to the rectifier.

When the airJ conditioning control switch is -moved to the C position, relay R4y is energized which -allows contactor ACI to close. Closing of contactor ACI starts the synchronous motor.

As the magnetic clutch is not energized under 4these conditions, the Diesel engine .remains at rest. As soon as the motor reaches the speed for which the centrifugal switch C-S, is set this closes the eld contactor F through the interlock on contactor ACI. This applies the eld and pulls the motorv into'synchronism. v v

The voltage regulator operates to maintain constant voltage onlthe A. C. supply lines by varying the ileld strength and the power factor.

At the same time' relay RI is energized, the bypass valve is energized 'through contacts on R3 and the compressor starts to operate and cool Kthe car.

the compressor without cooling the car. Con-v tactor AC3 can then again close and allow the rectifier to charge the battery.

It will be understood that while the interlock-v ing which prevents the rectifier being operated while the compressor is cooling is desirable in order to reduce the load on the system, it is not absolutely necessary. If the size of the Diesel engine or the capacity of the wayside supply is made suiciently large, the rectier can be operated at the same time that the compressor is cooling. The connections shown have been included to prevent its operation with a view of hunting the demand from either the Diesel engine or the Wayside supply.

Should the air conditioning control switch be moved to the olf position, the synchronous motor will be shut down by the opening of relay R4 and contactor AC I.

If the air conditioning control switch is moved to the H position relay RI will be closed. Closure of relay RI energizes the coil of contactor lACB connecting the heater to the A. C.supply. As soon as the car has heated up suiciently the contacts of 'I'HI will open and disconnect the heater from the line. It willbe noted that they rectifier and heater can be operated at the same time. This is necessary as the heater would probably be on most of the time in winter whereas the compressor would not be in summer. 1

Should the Diesel engine be started while the external A. C. supply is connected to the car, vthe circulated and not to furnish the entire heating and that additional heat will be provided in the car, preferably from the usual steam heat line, to provide the total necessary for proper heating.

This system is best adapted for Diesel engine drive for the following reasons:

1. For standby operation in terminals, it is necessary to operate from 220 volt, 3 phase A. C., and in order to avoid conversion losses the motor driving the compressor must be operated from A. C. supply. Y

2. An A. C., 220 volt 3 phase synchonous motor,

which can also be used as a generator, is lighter than a low voltage D. C. motor of the same rating.

3. Battery size can be reduced to a minimum, since the air conditioning'is never operated from it.

4. Lights can be .operated at most elcient voltage for incandescent lamps and new fluorescent lumiline lamps can readily be used.

5. Use of a rectifier avoids necessity of having an exciter or D. C. generator on the Diesel engine generator set thus keeping length to the minimum.

From the foregoing description, taken in connection with the drawings, the construction and mode of operation of my improved air conditioning and illuminating system for railway passenger cars will be readily understood without a further and extended description, and it will be seen that the invention provides a system which is simple of construction, reliable and eillcient in action and which reduces the number of working parts to a high degree as compared with other similar systems, thereby making the system relatively inexpensive in construction, installation and operation as compared with prior systems.

While the organization shown is preferred, itl

will, of course, be understood thatchanges in the construction, arrangement and operation of the parts of the system within the scope of the appended claims, may be made without departing from the spirit or sacrificing any of the advantages of the invention.

What I claim is:

1. In a system of the character described, an electric circuit, a compressor, an A. C. synchronous electric motor in said circuit adapted to operate at a predetermined speed, said motor being coupled to the compressor to drive the same, means for connecting said circuit and motor with an outside source of current for supplying current to the circuit and operating the motor as such to drive the compressor, an internal com- -bustion motor for driving the synchronous motor as a generator for `Supplying current to the circuit and for mechanically driving the compressor from the motor, and means operating when the internal combustion motor reaches a speed suitable for driving the synchronous motor at the predetermined speed for connecting said vinternal combustion motor to the synchronous motor.

2. In a system of the character described, 'an electric circuit, a compressor, an A. C. synchronous electric motor in said circuit designed to be driven at an assigned speed, said motor being means for'connecting said circuit and-motor with.'

coupled to the' compressor to drive the same, means for connecting said circuit and motor with an outside source of 'current for supplying current to the circuit and for operating the motor as such to drive the compressor, an internal combustion motor designed to be driven substantially at the same speed as the electric motor for driving the electric motor as a generator and driving the compressor therethrough, and a clutch automatically operating at the assigned speed for coupling said internal combustion'motor to the electric motor.

3. In a system `of the character described, an

electric circuit, a compressor, an A. C. synchrono us electric motor in said circuit designed to be driven at, an assigned speed, said motor being coupled'to the compressorto drive thejsame,

an outside source of current for'supplying current to the circuit and for operating the motor as such to drive the compressor, an internal combustionl motor for driving the electric motor asa generator and driving the compressor therethrough, and electrically operated means for connecting the internal combustion motor at the assigned speed with the electric motor.

4. In a system of the character described, an electric circuit, a compressor, an A. C. synchronous electric motor in said circuit designed to be driven at an assigned speed, said motor being coupled to the compressor to drive the same, means for connecting said circuit and motor with an outside source of current for supplying current to the circuit and operating the motor as such to drive the compressor, an internal combustion motor designed to be driven substantially at the same speed as the electric motor for driving the electric motor as a generator and driving the compressor therethrough, an electrically operated clutch for connecting the internal combustion motor at the assigned. speed with the electric motor, and means in the electric circuit for energizing and deenergizing the clutch.

5. Ina system of the character described, an electric circuit, a cooling unit. including a compressor, an electric motor in said circuit, said motor being coupled to the compressor to drive the same, an electric air heater in the circuit, means forv connect'ng said circuit and motor with an outside source of current for supplying current to the circuit and operating the motor as such to drive the compressor, temperature controlled means in the circuit for throwing the cooling unit yfor driving the electric motor as a generator and driving the compressor therethrough, and means for connecting said internal combustion motor t'oand disconnecting it from the electric motor.

6. In a system of the character described, an electric circuit, a cooling unit including a compressor, an electric motor in said circuit designed to be driven at an assigned speed, said motor being coupled to the compressor to drive the same, an electric air heater in the circuit, means for connecting said circuit and motor with an outside source of current for supplying current to the circuit and operating the motor as such to drive the compressor, thermally responsive means in the circuit for automatically throwing the cooling unit into action and the heater out of action and vice versa, an internal combustion motor designed to be driven substantially at the same speed as the electric motor for driving4 the electric motor as a generator and driving the compressor therethrough, said thermally responsive means acting to render the cooling unit inoperative without stopping the action of the compressor, and a clutch for coupling said internal combustion motor to and uncoupling it from the electric motor.

ing lcoupled to the compressor to drive the same,

means for connecting said circuit and motor with an outside source of current for supplying current to the circuit and operating the motor as `such to drive the compressor, an internal combustion motor for driving the electric motor as a generator and driving the compressor therethrough, and means for preventing-simultaneous application of outside and internal power to the circuit.

Vergizing the clutch, said means acting if set into 8. In asystem of the character described, an v electric circuit, a compressor, a synchronous electric motor in said circuit, said motor beingcoupled to the compressor to drive the same, means for connecting said circuit and motor with an outside source of current for supplying current to the circuit and operating the, motor as such to drive the compressor, an internal combustion motor for driving the electric motor as a generator and driving the compressor therethrough, and means for preventing excitation of the iield of the motor until the motor in action has reached substantially synchronous speed.

9. In a system of the character described, an electric circuit, a cooling unit including a compressor, an electric motor in said circuit, said motor being coupled to the compressor to drive the same, an electric air heater in the circuit, means for connecting said circuit andl motor with an outside source of currentfor supplying current to the circuit and operating the motor as such to drive the compressor, thermally responsive means in the circuit for manually or automatically at predetermined temperatures throwing the heaterinto action and the cooling unit out of action and vice versa, an internal combustien motor for driving the electric motor as a generator and driving the compressor therethrough, said thermally responsive means acting to render the cooling unit inoperative at a predetermined temperature without stopping the action of thecompressor, and means for connecting said internal combustion motor to and disconnecting it from the electric motor.

10. In a system oi' the character described, an electric circuit, a compressor, a synchronous motor in said circuit coupled to the compressor to drive the same, an internal combustion motor for driving the synchronous motor as a generator and driving the compressor therethrough, and means for connecting said circuit and synchronous motor with an outside source of current for supplying current to the circuit and operating the synchronous motor as such to drive the compressor.

11. In a system of the character described, an electric circuit, a compressor, a generator in said circuit designed to be driven at any assigned speed, said generator being coupled to the cornpressor to drive the same, an internal combustion motor designed to be driven at the same speed as the generator to drive. the compressor therethrough, an electromagnetic clutch for connecting the internal combustion motor with the generator when the driving motor speed .reaches the assigned speed and disconnecting it from the generator at lower speeds, and means in said circuit for controlling said clutch for opening and closing actions. l

12. In a system of the character described, an electric circuit, a compressor, a synchronous motor in said circuit designed to be driven at an assigned speed, said motor being coupled to the compressor to drive the same, aninternal combustion motor for driving the synchronous motor as a generator and driving the compressor therethrough, means for connecting said circuit and synchronous motor with an outside source of current for supplyingcurrent to the circuit and for operating the motor as such and driving the compressor therethrough, an electromagnetic clutch forl connecting the internal combustion motor with and disconnecting it from the synchronous motor, and manually controllable means for starting the internal combustion motor and enby-pass into action at a action at the ltime the synchronous motor is running as a motor to cut oil the supply of current from the outside source and energize the clutch.

13. In-asystem of the character described, an electric circuit, a cooling circuit employing a volatile refrigerant and including a compressor, a synchronous motor coupledto the compressor, a Diesel engine for-driving the motor as a generator to charge the circuit and for driving therethrough the compressor, a by-pass for operativelyv disassociating the compressor'from` the cooling circuit, and temperature-controlled means in the circuit for controlling the by-pass to throw the predetermined temperature and to render it inactive at higher temperatures.

14. In a system of the character described, an electric circuit, a compressor, a synchronous electric motor in said circuit operable also as a generator, said motor being coupled to the compressor to drive the same, a battery in the lectric circuit forl energizing the field of the .synchronous motor, means for connecting said circuit and motor with an outside source of current for supplying current to the circuit and operating the synchronous motor as suchvto drive the compressor, an internal combustion motor for driving the synchronous motor as a generator and driving the compressor therethrough, means for connecting the electric synchronous motor with an outside source of current, a voltage regulator electric circuit, a compressor, a synchronous motor in said circuit, said motor being coupled to the compressor to drive the same, and unloading means for said compressor, means for connecting said circuit and synchronous motor with an outside source of current for supplying current to the circuit and operating the motor as such to I drive the compressor, an internal combustion motor for driving the electric motor as a generator'and driving the compressor therethrough,`

means in the circuit for controlling the unloading `means, an electrically operated clutch for connecting the internal combustion motor with and disconnecting it from the electric motor, and means for energizing and deenergizing the clutch.

16. In a system of the character described, an electric circuit, a compnessor, a synchronous motor in the electric circuit adapted to be operated at an assigned speed and coupled to the compressor for driving the same, an internal combustion motor for .driving the synchronous motor as a generator, and means for preventing the application of the full compressor load until the synchronous motor has attained the assigned speed.

17. In a system of the character described, an electric circuit, a compressor, a synchronous motor in the electric circuit coupled to the compressor for driving the same, an internal combustion motor for driving the same asa generator to supply-internal power to the electric circuit, an outside source of. current for supplying power -as such, and `means for preventing simultaneous applicationl of outside and internal power to the electric circuit.

y18. 'In'a system of the character'described, a main electric circuit, a. starter circuit including a starting 'battery and a; rectifier for charging the same from the main circuit, a generator in the main circuit, a compressor, an AC synchronous motor for supplying current to the main vcircuit and coupled to the compressor to drive the same,

WILLIAM S. H. HAMILTON. 

